Have you ever wondered why a typical beaded necklace from the East, called a mala, is always strung with 108 beads? You'll find this to be the case not only in Hindu traditions but also Buddhist, Sikh, Jain and virtually any tradition that has it's roots in India. If you've ever been initiated into the use of a mantra you've probably been told to chant your mantra at least 108 times a day, not fifteen minutes a day. Why? In Japan the Zen temple bells ring 108 times to bring in the New Year. Obviously this number is significant. But why not a more rounded number like 100?
The early Vedic sages were renowned mathematicians and in fact invented our number system. 108 was definitely the number of choice for this simple reason: 108 represents the whole of existence. Here's some interesting reasons why:

1. The number 9 represents wholeness and 108 when added together equals 9. 1+0+8 = 9. Interestingly, if you multiply 9 times ANY number, the answer is always 9 when you add the numbers together. Try it! 1x9=9. 2x9=18. 1+8=9. 285x9=2565 2+5+6+5=18 1+8=9. 8543x9=76887 7+6+8+8+7=36 3+6=9 The logic behind this is that 9 represents wholeness or God and God times anything is always God since God is all there is!
   
2. The 9 planets travelling through the 12 signs constitutes the whole of existence. 9 x 12 = 108
   
3. The 27 nakshatras or lunar constellations each have 4 padas or parts. The 27 nakshatras are also spread over the 4 elements - fire, earth, air, water. This also constitutes the whole of existence. 27 x 4 = 108
   
4. Consider the powers of 1, 2, and 3 in math: 1 to 1st power = 1; 2 to 2nd power = 4 (2x2); 3 to 3rd power = 27 (3x3x3). 1x4x27 = 108. The logic behind this is that 1 represents 1 dimensional reality, 2 represents 2 dimensional reality, 3 represents 3 dimensional reality. When you multiply their powers together then you encompass the whole of existence.
   
5. The universe is made up of 108 elements according to ancient texts. The current periodic table claims a few more than 108.
   
6. The diameter of the Sun is 108 times the diameter of the earth (give or take a few miles).
   
7. The average distance from the earth to the Sun is equivalent to 108 Sun's in a row (give or take a few miles).
   
8. The average distance from the earth to the Moon is equivalent to 108 Moon's in a row (give or take a few miles).